Illinois Field / South Illinois Field and Radio Transmission Laboratory
First used around 1884,  Illinois Field served as the military drill and parading grounds of the University. It ran between Springfield and University Avenues, in the area currently occupied by North Engineering Quad. Named Athletic Park on May 15, 1892, it was renamed in 1896 as Illinois Field.  The University's first homecoming was conducted on the field in 1910 and  that year's graduating class dedicated a terra cotta structure known as Celebration Urn in the center of Illinois Field. Meant to house celebration bonfires, the Urn was rapidly damaged by the bonfires and removed from use.  In the early days of the University, freshmen were forced to wear small green caps which they burned in a bonfire at Illinois Field come May, after which they would "snake dance through the local theatre". 
By 1911-1912 the Athletic Association was in the planning stages of a new Illinois Field to run from Daniels Street to Gregory Street, from the train tracks to First Street, all 15 acres of which it had recently purchased. 
Among the early buildings that gradually encroached onto the Field was the Radio Transmission Laboratory, also known simply as "the Radio Lab". Built in 1926 and located immediately behind the Men's Gym Annex, this 1,500 square foot building cost $45,000 to build  and was a memorial gift from Boetius Sullivan to honor his father, the Honorable Roger C. Sullivan. By 1932 it served as the broadcasting home of WILL radio.  An addition was later put on in 1937.  On July 25, 1942, the Board of Trustees authorized the purchase of a $2,000 for an orgatron for the Radio Station. 
In its heyday, the field played host to the University baseball, track and field, and even football teams, with such luminaries as Red Grange making their mark on it. The final University game was played on the field May 7, 1986, when Illinois' baseball team defeated Western Illinois 6-1. 
Today, the name Illinois Field is kept alive by a playing field in south campus in deference to this famous field.